[...]
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1446,6 +1446,32 @@ struct tlbflush_unmap_batch {
> bool writable;
> };
>
> +struct memalloc_info {
> + /*
> + * 0: not doing __GFP_RECLAIM allocation.
> + * 1: doing non-recursive __GFP_RECLAIM allocation.
> + * 2: doing recursive __GFP_RECLAIM allocation.
> + */
> + u8 valid;
> + /*
> + * bit 0: Will be reported as OOM victim.
> + * bit 1: Will be reported as dying task.
> + * bit 2: Will be reported as stalling task.
> + * bit 3: Will be reported as exiting task.
> + * bit 7: Will be reported unconditionally.
> + */
> + u8 type;
> + /* Index used for memalloc_in_flight[] counter. */
> + u8 idx;
u8 __pad; is also needed perhaps.
> + /* For progress monitoring. */
> + unsigned int sequence;
> + /* Started time in jiffies as of valid == 1. */
> + unsigned long start;
> + /* Requested order and gfp flags as of valid == 1. */
> + unsigned int order;
> + gfp_t gfp;
> +};
> +
[...]
> +
> +/*
> + * check_memalloc_stalling_tasks - Check for memory allocation stalls.
> + *
> + * @timeout: Timeout in jiffies.
> + *
> + * Returns number of stalling tasks.
> + *
> + * This function is marked as "noinline" in order to allow inserting dynamic
> + * probes (e.g. printing more information as needed using SystemTap, calling
> + * panic() if this function returned non 0 value).
> + */
> +static noinline int check_memalloc_stalling_tasks(unsigned long timeout)
> +{
> + char buf[256];
> + struct task_struct *g, *p;
> + unsigned long now;
> + unsigned long expire;
> + unsigned int sigkill_pending = 0;
> + unsigned int exiting_tasks = 0;
> + unsigned int memdie_pending = 0;
> + unsigned int stalling_tasks = 0;
> +
> + cond_resched();
> + now = jiffies;
> + /*
> + * Report tasks that stalled for more than half of timeout duration
> + * because such tasks might be correlated with tasks that already
> + * stalled for full timeout duration.
> + */
> + expire = now - timeout * (HZ / 2);
> + /* Count stalling tasks, dying and victim tasks. */
> + preempt_disable();
> + rcu_read_lock();
> + for_each_process_thread(g, p) {
> + u8 type = 0;
> +
> + if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
> + type |= 1;
> + memdie_pending++;
> + }
> + if (fatal_signal_pending(p)) {
> + type |= 2;
> + sigkill_pending++;
> + }
> + if ((p->flags & PF_EXITING) && p->state != TASK_DEAD) {
> + type |= 8;
> + exiting_tasks++;
> + }
> + if (is_stalling_task(p, expire)) {
> + type |= 4;
> + stalling_tasks++;
> + }
> + if (p->flags & PF_KSWAPD)
> + type |= 128;
> + p->memalloc.type = type;
> + }
The numbers assigned to type may be replaced with texts,
for instance,
MEMALLOC_TYPE_VICTIM
MEMALLOC_TYPE_DYING
MEMALLOC_TYPE_STALLING
MEMALLOC_TYPE_EXITING
MEMALLOC_TYPE_REPORT
> + rcu_read_unlock();
> + preempt_enable();
> + if (!stalling_tasks)
> + return 0;
> + cond_resched();
> + /* Report stalling tasks, dying and victim tasks. */
> + pr_warn("MemAlloc-Info: stalling=%u dying=%u exiting=%u victim=%u
> oom_count=%u\n",
> + stalling_tasks, sigkill_pending, exiting_tasks, memdie_pending,
> + out_of_memory_count);
> + cond_resched();
> + sigkill_pending = 0;
> + exiting_tasks = 0;
> + memdie_pending = 0;
> + stalling_tasks = 0;
> + preempt_disable();
> + rcu_read_lock();
> + restart_report:
> + for_each_process_thread(g, p) {
> + bool can_cont;
> + u8 type;
> +
> + if (likely(!p->memalloc.type))
> + continue;
> + p->memalloc.type = 0;
> + /* Recheck in case state changed meanwhile. */
> + type = 0;
> + if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
> + type |= 1;
> + memdie_pending++;
> + }
> + if (fatal_signal_pending(p)) {
> + type |= 2;
> + sigkill_pending++;
> + }
> + if ((p->flags & PF_EXITING) && p->state != TASK_DEAD) {
> + type |= 8;
> + exiting_tasks++;
> + }
> + if (is_stalling_task(p, expire)) {
> + type |= 4;
> + stalling_tasks++;
> + snprintf(buf, sizeof(buf),
> + " seq=%u gfp=0x%x(%pGg) order=%u delay=%lu",
> + memalloc.sequence, memalloc.gfp,
> + &memalloc.gfp,
> + memalloc.order, now - memalloc.start);
> + } else {
> + buf[0] = '\0';
> + }
> + if (p->flags & PF_KSWAPD)
> + type |= 128;
ditto
thanks
Hillf
